The printing of electronic devices such as, for example, thin film transistors (TFTs) has become of interest as a way to make electronic devices without incurring the costs associated with the equipment and processes traditionally used in the semiconductor industry. Ink jet printing can be particularly useful because it allows for discrete material placement.
One area of concern, however, in printed electronics is the performance of the semiconductor. The performance of the semiconductor depends upon charge carrier transport along the semiconductor molecules and facile transfer between the molecules. A more orderly arrangement of the molecules therefore produces higher charge carrier mobility. In order to achieve the most orderly arrangement of molecules, the semiconductor must generally be deposited from the vapor phase by vapor sublimation. The vacuum sublimation process, however, requires expensive equipment and lengthy pump-down cycles. But, solution deposition typically does not provide the highly ordered arrangement of molecules required for good charge carrier mobility. The charge carrier mobility of printed electronic devices can therefore be several orders of magnitude lower than that of electronic devices having a vapor deposited semiconductor.